Metal Oxide Cluster-Integrated Polymer Networks for Robust Solid-State Single-Ion Conduction at High Temperatures

Abstract

Ion conduction at high temperatures is critical to the improvement of the working efficiency and stability of energy conversion and storage devices and generally, ceramics and highly rigid polymers are applied; however, their poor processability and mechanical properties hindered their extensive applications. Herein, sub-nm anionic metal oxide cluster ({V6O13[(OCH2)3CR]2}2-) is covalently integrated in polymer networks for high temperature solid state single-ion electrolytes of H+ and Li+. The hexavandate cluster is functionalized with acrylate groups and it serve as nanoscale bifunctional crosslinker to copolymerize with poly(ethylene glycol) methacrylate for polymer network fabrication. The associated counter-cations of the immobilized hexavanadate can be fully solvated in the melts of poly(ethylene glycol) for high mobilities, contributing to the promising single ion conductivities with Li+ transference as 0.84. Suggested from dielectric spectroscopy studies, the transport of Li+ is directly mediated by the side chain dynamics. The counter-cations can be feasibly switched for the conductions of various cations, e.g., H+ and Li+. Meanwhile, the covalent and supramolecular interaction between polymers and inorganic hexavanadate afford enhanced stability and robust ionic conduction at temperature as high as 200 °C. The work provides versatile platform chemical systems for robust solid-state single-ion conduction at high temperatures.